Construction of an Electron Capture and Transfer Center for Highly Efficient and Selective Solar-Light-Driven CO 2 Conversion.

Exploring high-efficiency photocatalysts for selective CO 2 reduction is still challenging because of the limited charge separation and surface reactions. In this study, a noble-metal-free metallic VSe 2 nanosheet was incorporated on g-C 3 N 4 to serve as an electron capture and transfer center, activating surface active sites for highly efficient and selective CO 2 photoreduction. Quasi in situ X-ray photoelectron spectroscopy (XPS), soft X-ray absorption spectroscopy (sXAS), and femtosecond transient absorption spectroscopy (fs-TAS) unveiled that VSe 2 could capture electrons, which are further transferred to the surface for activating active sites. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations revealed a kinetically feasible process for the formation of a key intermediate and confirmed the favorable production of CO on the VSe 2 /PCN (protonated C 3 N 4 ) photocatalyst. As an outcome, the optimized VSe 2 /PCN composite achieved 97% selectivity for solar-light-driven CO 2 conversion to CO with a high rate of 16.3 μmol·g -1 ·h -1 , without any sacrificial reagent or photosensitizer. This work offers new insights into the photocatalyst design toward highly efficient and selective CO 2 conversion.